 This has found wider use across the world in more recent years with the invention of steel, as it allows for the dome to be supported without the need for massive arches and columns which were main features of the older cruciform churches.The iconostasis, also called the "τεμπλον/templon", it is a screen or wall between the nave and the sanctuary, which is covered with icons.There will normally be three doors, one in the middle and one on either side.